Building, Running and Analyzing Different Types of Fluid Models (Dry Gas, Wet Gas, Gas Condensate) (Volatile Oil, Black Oil, Heavy Oil)
Using
WinProp
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Exercise 1 (Required File: Five Fluid Types Data.xls) Objective: Modelling of five fluid type i.e. Dry gas, wet gas, Gas condensate, volatile oil and Black oil. 1. Double click on the WinProp icon in the Launcher and open the WinProp interface. 2.
Double click on “Titles/EOS/Units” and write “Dry gas/Wet gas/Gas condensate/Volatile oil/Black oil” in the comments and the Title1 section depending on the case you are modelling. Select PR 1978 and the equation of state to be used in characterizing the fluid model, select “Psia & deg F” as the units and Feed as mole. Click “OK”.
3. Open “component selection” form and insert the library components in the following order: CO2, N2, C1, C2, C3, IC4, NC4, IC5, NC5, and FC6. (The order of selection in important!). +
4. In all cases except “Dry Gas” also, characterize the C7 fraction with a single pseudocomponent by inserting a user defined component. Click on “options” button in the “component definition form” and select “insert own component” based on specific gravity (SG), boiling point (TB) and molecular weight (MW). Use the properties given in the file: “Five Fluid Types Data.xls”. Your component definition form should look like Figure1 for Dry gas and Figure 2 in case of other fluid types.
Figure1: Component definition for case of Dry Gas
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5. Open the "composition form" and input the mole fractions of the primary composition as mentioned in the file: “Five Fluid Types Data.xls”. The “secondary” corresponds to the injection fluid (if applicable). 6. Insert “two phase flash calculation form" into the WinProp interface. Open this form by double clicking on it and under the comments section type “Standard condition flash”. We are planning to perform a flash at 14.7 Psia and 60 deg.F. Leave other calculation options as default. The feed composition is subjected to mixed i.e. primary and secondary composition. The “two-phase flash calculation form should look like as shown in Figure 3. 7. Insert “Saturation pressure calculation Form" into the WinProp Interface to perform a saturation pressure calculation at the reservoir temperature. 8. Double click and open the saturation pressure calculation form. Under the comments type “Psat at reservoir temperature”. Also, input the reservoir temperature and saturation pressure estimate as 180 ºF and 1000 Psia respectively. The input value of “saturation pressure estimate” is used as an initial guess by WinProp during the iteration processes for calculating the actual saturation pressure. 9. We would also like to generate a pressure-temperature phase diagram. Insert a “two-phase Envelope” form in the Main WinProp interface. Open the form by double clicking on it and type in “P-T envelope” under the comments section. Input the data as shown in Figure 4.
Figure 2: Component definition for other fluid types
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Figure 3: Two phase flash calculation at standard condition.
Figure 4: Input data for two-phase envelop calculation.
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10. Create plots of phase properties vs. pressure at the reservoir temperature using the 2-phase flash calculation. Examples of properties which may be plotted are: Zfactors, phase fractions, densities, molecular weights, K-values, etc. This can be done by adding another Two-phase Flash calculation from. Type in comments as “Phase properties as function of pressure”. Input the reservoir temperature as 180 deg F, temperature step as 0 and No. of temperature step as 1. Input the reservoir pressure as 250 Psia, pressure step of 250 Psia and No. of pressure steps as 12 for dry and wet gas case whereas 24 for gas condensate, volatile oil and black oil. The reservoir temperature would also change depending on the case you are modelling as mentioned in the file: “Five Fluid Types Data.xls” 11. In the plot control tab of “two-phase calculation” form select the properties depending on the case as follows: No. 1 2 3
Case Dry Gas Wet gas Gas Condensate, Volatile Oil & Black oil
Plot Property Z compressibility factor Z compressibility factor Phase volume fraction, Z factor, K-values (y/x)
12. For all the oil cases, add a single-stage separator calculation with separator pressure of 100 psia and separator temperature of 75 F. 13. The final WinProp interface should look like Figure 5.
Figure 5: WinProp interface for modeling Dry Gas case.
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14. Save the WinProp file as ‘drygas.dat’ and run it 15. Repeat Items 1 to 14 and build a dat file for other types of fluid and save them as ‘wetgas.dat’, ‘gascondensate.dat’, ‘volatileoil.dat’, ‘blackoil.dat’ files respectively and then run. Note: You are now able to analyze the results in terms of the criteria for definition of each of the fluid types. The plots for different cases are shown in Figures 6 to 14. Dry Gas P-T envelope : P-T Diagram 1400
Pressure (psia)
1200 1000 800 600 400 200 0 -100.0
-80.0
-60.0
-40.0
-20.0
0.0
20.0
Tem perature (deg F) 2-Phase boundary
Critical
Figure 6: 2-Phase P-T diagram for Dry Gas case. Dry Gas Phase properties as fn(P) : Phase Properties (Solvent 0.98 Mole Fraction = 0.0000)
Vapor Z-Factor
0.96 0.94 0.92 0.90 0.88 0.86 0.84 0
500
1000
1500
2000
2500
3000
3500
Pressure (psia) 180.00 deg F
Figure 7: Vapor Z factor for Dry gas case. 6
Wet gas P-T envelope : P-T Diagram 3000
Pressure (psia)
2500 2000 1500 1000 500 0 -100
-50
0
50
100
150
200
250
Tem perature (deg F) 2-Phase boundary
Figure 8: 2-Phase P-T diagram for Wet Gas case. Wet gas Phase properties as fn(P) : Phase Properties (Solvent 0.98 Mole Fraction = 0.0000)
Vapor Z-Factor
0.96
0.94
0.92
0.90 0
500
1000
1500
2000
2500
3000
3500
Pressure (psia) 220.00 deg F
Figure 9: Vapor Z factor for wet gas case
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Gas condensate P-T envelope : P-T Diagram 12,000 10,000 Pressure (psia)
8,000 6,000 4,000 2,000 0 -100
0
100
200
300
400
500
600
Tem perature (deg F) 2-Phase boundary
Critical
Figure 10: 2-Phase P-T diagram for Gas condensate case. Gas condensate Phase properties as fn(P) : Phase Properties (Solvent Mole Fraction = 0.0000)
Gas condensate Phase properties as fn(P) : Phase Properties (Solvent Mole Fraction = 0.0000) 105 Vapor Phase Volume %
Liquid Phase Volume %
35.0 30.0 25.0 20.0 15.0 10.0 5.0 0.0
95 90 85 80 75 70 65
0
1000
2000
3000
4000
5000
6000
0
7000
1000
2000
3000
4000
Pressure (psia)
Pressure (psia)
280.00 deg F
280.00 deg F
Gas condensate Phase properties as fn(P) : Phase Properties (Solvent Mole Fraction = 0.0000) 1.20
1.15
1.00
1.10
0.80 0.60 0.40 0.20 0.00
5000
6000
7000
Gas condensate Phase properties as fn(P) : Phase Properties (Solvent Mole Fraction = 0.0000)
Vapor Z-Factor
Liquid Z-Factor
100
1.05 1.00 0.95 0.90
0
1000
2000
3000
4000
5000
6000
7000
0
1000
2000
3000
4000
Pressure (psia)
Pressure (psia)
280.00 deg F
280.00 deg F
5000
6000
7000
Figure 11: Phase volume fractions and Z factors for gas condensate
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K val. (vapor / liq.) (Temperature = 280.00 deg F)
Gas condensate Phase properties as fn(P) : Phase Properties (Solvent 1.00E+02 Mole Fraction = 0.0000) 1.00E+01 1.00E+00 1.00E-01 1.00E-02 1.00E-03 0
1000
2000
3000
4000
5000
6000
7000
Pressure (psia)
CO2
N2
C1
C2
IC5
NC5
FC6
C7+
C3
IC4
NC4
Figure 12: K value for gas condensate case. Volatile oil P-T envelope : P-T Diagram 20,000
Pressure (psia)
15,000
10,000
5,000
0 -200
0
200
400
600
800
Tem perature (deg F) 2-Phase boundary
Critical
Figure 13: 2-Phase P-T diagram for Volatile oil case.
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Black oil P-T envelope : P-T Diagram 3000
Pressure (psia)
2500 2000 1500 1000 500 0 -200
0
200
400
600
800
1000
1200
Tem perature (deg F) 2-Phase boundary
Critical
. Figure 14: 2-Phase P-T diagram for Black oil case. Additional Practice: For the black oil data case, investigate the effect on the simulated separator calculation induced by changing the following parameters: • Apply the volume shift correlations • Set the hydrocarbon binary interaction parameters to zero • Reduce the C7+ Pc by 20% 16. To set volume shift to correlations, double click ‘Component Selection/Properties’ and click on ‘VolumeShift’ tab, choose ‘Reset to correlation values’ then save as 'blackoil1_volshift correlation value.dat' file. Go back to the VolumeShift tab again and click on "Reset to Zero's" and save as 'blackoil1_volshift set to zer.dat' file. Run both data files and compare the results on Separator calculation. It should look like to the following outputs: Separator output with Volshift set to zero: Oil FVF = vol of saturated oil at 2877.86 psia and 170.0 deg F per vol of stock tank oil at STC(4) = 1.111 API gravity of stock tank oil at STC(4) = 58.10 Separator output with Volshift set to correlation value: Oil FVF = vol of saturated oil at 2877.86 psia and 170.0 deg F per vol of stock tank oil at STC(4) = 1.137 API gravity of stock tank oil at STC(4) = 32.77
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17. Open ‘blackoil.dat’ again and set hydrocarbon binary interaction parameter to zero, by double clicking at ‘Component Selection/Properties’ . Click on ‘Int. Coef.’ tab and click on ‘HC-HC Group / Apply value to multiple non HC-HC pair…’ Check on 'HC-HC' and change Exponent value to zero and press 'OK' twice. Save as a new name and see the result at Separator calculation. It should be like following: Oil FVF = vol of saturated oil at 2027.10 psia and 170.0 deg F per vol of stock tank oil at STC(4)= 1.115 API gravity of stock tank oil at STC(4) = 58.15.
18. To reduce the C7+ Pc by 20%, double click ‘Component Selection/Properties’ and change the Pc value of C7+ to 12.36 and see the result again it should be like:( make sure to save the file in new name). Oil FVF = vol of saturated oil at 2142.23 psia and 170.0 deg F per vol of stock tank oil at STC(4) = 1.100 API gravity of stock tank oil at STC(4) =104.78
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WinProp Exercise 2 Objective: To determine the MMP and MME for a rich gas injection flood into the reservoir (Like CO2 Flooding) Starting with the black oil data set from Exercise 1, create P-X phase diagrams at the reservoir temperature for the following injection fluids: 1. Addition of secondary stream with the following compositions: • Pure N2 • Pure CO2 • Dry gas (from Exercise 1) • A rich gas stream with the composition (in mole %): CO2 1.4 N2 1.0 C1 33.2 C2 23.3 C3 25.3 IC4 3.8 NC4 9.6 IC5 2.1 NC5 0.3 The required forms and their arrangement of the calculation options in WinProp interface should look like as shown in Figure 15 for this case. Save this file as ‘blackoil_richgas_MMP_MME.dat’
Figure 15: Addition of solvents in black oil and calculation of MMP and MME 12
2. Run a multi-contact miscibility calculation to determine the MMP for pure rich gas injection. Insert a Multiple-contact miscibility calculation form and input the data shown in Figures 16 and 17 presented below.
Figure 16: Input data for calculation of MMP.
Figure 17: Rich gas (make-up gas) composition for calculation of MMP.
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Analyze the output file for results of single contact miscibility and multi-contact miscibility pressures and mole fraction of make-up gas. SUMMARY OF MULTIPLE CONTACT MISCIBILITY in *.OUT file CALCULATIONS AT TEMPERATURE = 170.000 deg F ______________________________________________ FIRST CONTACT MISCIBILITY ACHIEVED AT PRESSURE 0.49800E+04 Psia MAKE UP GAS MOLE FRACTION = 0.10000E+01 MULTIPLE CONTACT MISCIBILITY ACHIEVED AT PRESSURE = 0.38400E+04 Psia MAKE UP GAS MOLE FRACTION = 0.10000E+01 BY BACKWARD CONTACTS - CONDENSING GAS DRIVE
3. Run a multi-contact miscibility calculation to determine the minimum amount of rich gas necessary to add to the dry gas to achieve miscibility at 4500 psi (MME calculation). For this insert the “Multiple-contact miscibility calculation” form and input the following parameters. Notice that in this case only one pressure value is used at which the miscibility is desired. In the composition form the starting point for the make-up gas fraction is from 50%.
Figure 18: Input data for calculation of MME calculation.
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Figure 19: Rich gas (make-up gas) composition for calculation of MME.
Analyze the output file for results of single contact miscibility and multi-contact miscibility pressures and mole fraction of make-up gas. SUMMARY OF RICH GAS MME CALCULATIONS AT TEMPERATURE =
170.000 deg F
FIRST CONTACT MISCIBILITY PRESSURE (FCM) IS GREATER THAN 0.45000E+04 psia MULTIPLE CONTACT MISCIBILITY ACHIEVED AT PRESSURE = 0.45000E+04 psia MAKE UP GAS MOLE FRACTION = 0.92000E+00 BY BACKWARD CONTACTS - CONDENSING GAS DRIVE
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Exercise 3: Raleigh Oil (Required File: Raleigh black oil-data.xls) Objective: Plus fraction splitting, matching experimental constant composition expansion, separator test and differential liberation tests. 1. Initialize WinProp through CMG launcher. 2. Insert a title: “plus fraction characterization” and select PR (1978), Psia & deg F, feed as moles in the “specify titles, EOS and unit system” form. 3. In the component selection/Properties form add the following library components and compositions as given in the file: “Raleigh black oil-data.xls”.
Figure 20: black oil composition for Raleigh oil. 4. To split the C7+ fraction into pseudocomponents; double click on “Plus fraction Splitting" form. on "General" Tab; Specify Gamma distribution function, 4 pseudocomponents, The first single carbon number in plus fraction as7 and leave others as default Go to "Sample 1" Tab.
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Figure 21: Plus fraction splitting for Raleigh Oil. 5. Input the MW+ as 190, SG+ as 0.8150 and Z+ (mole fraction of C7+ fraction) as 0.2891. Make sure alpha is equal to 1. 6. Save the dataset as ‘raleigh oil.dat’ and run it. After running the data set, use the “Update component properties” in the File menu. And save the data set as ‘raleigh oil_plus fraction splitting.dat’. You will now notice that 4 hypothetical pseudo components have been added in the components form. 7. In order to match the CCE, Differential liberation and separator test, use the data given in the file “Raleigh black oil-data1.xls”. then open "Saturation Pressure", "constant composition expansion", "separator" "differential liberation" forms in sequence. Input the experimental data given in the file “Raleigh black oil-data1.xls”.( you can also input all above forms, from another WinProp dataset). 8. On the “Component Selection/properties” form, set the volume shifts to the correlation values. Save your model as ‘raleigh oil_experimental data.dat’ and run it once to validate your model and check for errors in the input data.
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9. Click on Regression /start on top menu and open Open "Regression Parameters" form before "Saturation Pressure" form( before any regression calculation) and insert " End Regression " form at end(after all forms that are supposed to be included in regression process, i.e. CCE, Saturation Pressure, Differential Liberation and Separator ). This defines the “Regression Block.” 10. Select the heaviest pseudocomponent’s Pc and Tc, volume shifts of all C7+ pseudocomponents and C1, and the hydrocarbon interaction coefficient exponent as regression variables. Set the convergence tolerance to 1.0E-06 in "Regression Controls" tab and then save and run the data set.
Figure 22: Regression control for experimental data matching. 11. Adjust the weight of some key experimental data points. Try setting the weight for separator API gravity to 5.0, saturation pressure to 10.0, and differential liberation API gravity at std conditions to 0.0. Re-run the regression. 12. In some cases, you may have to change the lower and upper bounds of the regression parameters depending on whether these bounds are reached during the regression. In this case the following bounds were used:
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Figure 23: Variable bounds used during the regression. 13. Analyze the *.out file and refer to the summary of Regression Results for comparison of the experimental versus calculated values. 14. After completing the match to the PVT data, update the component properties and again save the file under a new name as ‘raleigh oil_experimental data_vis.dat’ in preparation for viscosity matching. 15. For viscosity matching, temporarily exclude the saturation pressure, constant composition expansion and separator calculations from the data set by rightclicking on each option and selecting “Exclude” from the pop-up menu. 16. In the "Differential Liberation" form, set the weight for the viscosity data to 1.0, and all other weights to 0.0. 17. On the viscosity parameters tab of the "Regression Parameters" form, remove all previously selected parameters, and then select “Vc, vis(l/mol)” for C1 and the C7+ pseudo components as regression variables. Run the data set. 18. After completing the match to the viscosity data, update the component properties and save the file under a new name ‘raleigh oil_Blackoil PVT.dat’ in preparation for generating the IMEX PVT table. 19. Remove the regression forms and include any options that had previously been excluded. Add a “Black Oil PVT Data” option at the end of the data set.
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20. On the ‘Black Oil PVT Data’ form, enter the saturation pressure data, desired pressure levels and the separator data. Enter mole fractions of 0.1, 0.2 and 0.3 for the swelling data.
Figure 24: Black oil PVT export for IMEX.
Figure 25: Pressure levels for back oil PVT 20
Figure 26: Water properties for back oil PVT 21. Leave the “Oil Properties” controls at the defaults, and then select “Use solution gas composition…” for the swelling fluid specification on the “gas properties” tab. Run the data set.
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